In U.S. Pat. Nos. 4,818,998 and 4,908,629 of common assignee with the present invention, an automobile theft detection system and method is disclosed, using concealed transponders in equipped vehicles which respond to police or other broadcast signals sent upon notification of theft of a vehicle, providing periodic encoding to transponder reply signals unique to the vehicle for receipt by a recovery police car to home in on and track in order to recover or locate the vehicle.
This system has been working admirably well for a number of years as described, for example, in the assignee's 1989 brochure entitled "LoJack Stolen Vehicle Police Recovery Network".
There are occasions, however, where the vehicle operator may actually be present in a vehicle when the operator or vehicle is threatened, and in which it would be most advantageous for the operator, totally independently of the automatic stolen vehicle operation of the vehicle transponder, promptly, simply and directly to access the system, by manual button or other control, instantly to activate the transponder to begin sending its periodic coded identification signals--this time as an indication of panic or emergency or the like--with the police system thus alerted to locate the vehicle, just as if it had been stolen.
Similarly, even before the vehicle owner learns that the vehicle has been stolen, it is also possible synergistically to use the transponder system, again totally independently of the automatic stolen vehicle operation, when some preliminary unauthorized action is taken against the vehicle; for example, tampering or starting to rock or otherwise move the vehicle, or altering the engine starter circuit or by applying "hot wiring".
It is to the ready incorporation of these important added uses of the same transponder system, irrespective of and without interfering with the automatic stolen vehicle operation of the system, that the present invention is thus primarily directed.